Currents Exit Causes of Currents Controlled by several

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Currents Exit

Currents Exit

Causes of Currents Controlled by several things: 1. Global winds 2. Coriolis Effect 3.

Causes of Currents Controlled by several things: 1. Global winds 2. Coriolis Effect 3. Position of continents 4. Density of seawater Warms or cools the air above it, influencing the climate of land near the coast Menu Previous Next 11 - 2

Coriolis effect http: //www. youtube. com/watch? v=i 2 mec 3 vgea. I Coriolis effect

Coriolis effect http: //www. youtube. com/watch? v=i 2 mec 3 vgea. I Coriolis effect by nova pbs 3 min http: //www. youtube. com/watch? v=dt_XJp 77 -mk 2 guys and a ball on a rotating platform by TSGPhysics Menu Previous Next 11 - 3

Causes of Currents Variations in water density When density of seawater in one area

Causes of Currents Variations in water density When density of seawater in one area is greater than in a neighboring area, it initiates a current Density Currents are a type of vertical current that carries water from the surface to deeper parts of the ocean Current flows below the surface as more dense water sinks below less dense water Menu Previous Next

Cold Water Density Current Menu Previous Next 11 - 5

Cold Water Density Current Menu Previous Next 11 - 5

Causes of Currents Changes in sea level Sea level is the average level of

Causes of Currents Changes in sea level Sea level is the average level of the sea’s surface at its mean height between high and low tide The ocean’s surface is never flat, ocean circulation cause slopes to develop The steeper the “mound” of water, the larger and faster the current The force that drives this current is the pressure gradient force Menu Previous Next

 Satellite images show the ocean is “hilly, ” not calm or flat water

Satellite images show the ocean is “hilly, ” not calm or flat water piles up where currents meet where currents diverge, “valleys” form Menu Previous Next http: //www. ifm. zmaw. de/research/remote-sensing-assimilation/ssh-and-currents/

Causes of Currents Deep and shallow areas of the sea have currents Surface currents

Causes of Currents Deep and shallow areas of the sea have currents Surface currents are generally from 0 to about 400 meters (1, 300 feet), although some go much deeper Different phenomena drive surface and deep currents ocean boundaries force currents to turn; they can’t just keep going in a particular direction Wind If the wind blows long enough in one direction, it causes a water current to develop The current continues to flow until friction dissipates its energy Near the equator- winds blow ocean water east to west Closer to the poles – ocean water is blown west to east The trade winds and the westerlies account for most the Earth’s wind energy Menu Previous Next 11 - 8

Wind cells cause currents Menu Previous Next 11 - 9

Wind cells cause currents Menu Previous Next 11 - 9

Gyres combination of westerlies, trade winds, and the Coriolis effect results in a circular

Gyres combination of westerlies, trade winds, and the Coriolis effect results in a circular flow in each ocean basin 5 total Menu Previous Next

Ekman Transport because of the Coriolis effect: Currents have a tendency to flow to

Ekman Transport because of the Coriolis effect: Currents have a tendency to flow to the right in the Northern Hemisphere flow to the left in the Southern Hemisphere This results in an interesting phenomenon called Ekman transport was discovered in the 1890 s by Fridtjof Nansen Menu Previous Next 11 - 11

Ekman Transport net motion imparted to the water column down to friction depth called

Ekman Transport net motion imparted to the water column down to friction depth called the Ekman transport Ekman Spiral Menu Previous Next

Ekman Transport Wind and the Coriolis effect influence water below the surface because water

Ekman Transport Wind and the Coriolis effect influence water below the surface because water flows in layers Due to friction, the upper water currents push the water below it. This deeper layer pushes the next layer below it. The process continues downward. Each water layer flows at an angle to the layer above causing a spiral motion Ekman spiral= spiraling effect of water layers pushing slightly to the right from the one above in the Northern Hemisphere (90° to the right of the wind ) to the left (90° to the left ) in the Southern Hemisphere Menu Previous Next

Dynamic balance between the clockwise deflection of the Coriolis effect (attempting to move water

Dynamic balance between the clockwise deflection of the Coriolis effect (attempting to move water to the right) and the pressure gradient created by gravity (attempting to move the water to the left) The balance keeps the gyre flowing around the outside of the ocean basin. Menu Previous Next

Western/Eastern Ocean Boundary Currents currents are created by the Earth’s rotation results from the

Western/Eastern Ocean Boundary Currents currents are created by the Earth’s rotation results from the balance between the pressure gradient force and the Coriolis effect. Characteristics of boundary currents. Menu Previous Next

Western/Eastern Ocean Boundary Currents Western boundary currents are found on the east coasts of

Western/Eastern Ocean Boundary Currents Western boundary currents are found on the east coasts of the continents Stronger and faster than eastern boundary currents flow through smaller areas than eastern boundary currents Formation of eddies. Menu Previous Next

Western/Eastern Ocean Boundary Currents Trade winds blow along the equator pushing water westward causing

Western/Eastern Ocean Boundary Currents Trade winds blow along the equator pushing water westward causing it to “pile up” on the western edge of ocean basins before it turns to the poles earth’s rotation tends to shift the higher surface level in the center of the gyre westward. higher surface level is now west of center and forces the current to “squeeze” through a narrower area Western ocean boundary currents handle the same volume, but through smaller areas, so water must move more rapidly Menu Previous Next

Countercurrents Another water flows in directions that differ from the major ocean currents Countercurrents

Countercurrents Another water flows in directions that differ from the major ocean currents Countercurrents are associated with equatorial currents. A countercurrent runs in the opposite direction of its adjacent current North Equatorial Current (NEC) and South Equatorial Current (SEC) flow west until they encounter continents Menu Previous Next

Countercurrents Menu Previous Next

Countercurrents Menu Previous Next

Undercurrents - Cromwell An undercurrent flows beneath the adjacent current instead of beside it.

Undercurrents - Cromwell An undercurrent flows beneath the adjacent current instead of beside it. Pacific’s Cromwell Current, named for Townsend Cromwell, who discovered it in 1956 Cromwell Current flows more than 14, 000 kilometers (8, 700 miles) from New Guinea to Ecuador depth of approximately 100 to 200 meters (300 to 600 feet). average speed of 5 kilometers (3 miles) per hour and carries a volume about half that of the Gulf Stream Since the discovery of the Cromwell Current, undercurrents have been found beneath most major currents Menu Previous Next

Upwelling and Downwelling Upwelling an upward vertical current that brings deep water to the

Upwelling and Downwelling Upwelling an upward vertical current that brings deep water to the surface Downwelling a downward vertical current that pushes surface water to the bottom Menu Coastal Upwelling Previous Next

Upwelling and Downwelling Coastal upwellings occur when the wind blows offshore or parallel to

Upwelling and Downwelling Coastal upwellings occur when the wind blows offshore or parallel to shore In the Northern Hemisphere – this wind blowing southward will cause an upwelling only on a west coast the same wind on an east coast sends surface water toward shore causing a downwelling Menu Previous Next

Upwelling and Downwelling These currents have strong biological effects: Upwelling brings deepwater nutrients up

Upwelling and Downwelling These currents have strong biological effects: Upwelling brings deepwater nutrients up into shallow water Upwellings relate to significant weather patterns Downwellings remove organic nutrients from the surface, carrying and re-cycling nutrients to deep ocean ecosystems and sediments Downwelling reduces productivity of some surface species and increases productivity of some bottom species Menu Previous Next

Upwelling and Downwelling Equatorial Upwelling Menu Previous Next

Upwelling and Downwelling Equatorial Upwelling Menu Previous Next

Heat Transport and Climate Currents play a critical role by transporting heat from warm

Heat Transport and Climate Currents play a critical role by transporting heat from warm areas to cool areas, moderating temperatures Without currents moving heat, the world’s climates would be more extreme The Earth’s cold regions would be colder and the warm regions would be warmer Winters in northern Europe would be significantly colder without the Gulf Stream bringing heat from the tropics Southern California owes its mild climate to the moderating effects of the Pacific Ocean. The southerly current along the California coast brings cool water from the north, keeping southern California cooler than it would otherwise be in the summer Menu Previous Next

El Nino Nov 2013 http: //www. ssec. wisc. edu/data/sst/latest_sst. gif Menu Previous Next 11

El Nino Nov 2013 http: //www. ssec. wisc. edu/data/sst/latest_sst. gif Menu Previous Next 11 - 26

La Nina http: //www. osdpd. noaa. gov/data/sst/anomaly/anomnight. current. gif Menu Previous Next 11 -

La Nina http: //www. osdpd. noaa. gov/data/sst/anomaly/anomnight. current. gif Menu Previous Next 11 - 27

El Nino http: //www. youtube. com/watch? v=Db. Nzw 1 CCKHo Visualizing el nino from

El Nino http: //www. youtube. com/watch? v=Db. Nzw 1 CCKHo Visualizing el nino from nasa Menu Previous Next 11 - 28

El Niño Southern Oscillation every 3 to 8 years a rearrangement of the high-

El Niño Southern Oscillation every 3 to 8 years a rearrangement of the high- and low-pressure systems occur reasons are still not clear Normal Menu El Niño Previous Next

El Niño Southern Oscillation El Niño tremendously affects world weather patterns brings low pressure

El Niño Southern Oscillation El Niño tremendously affects world weather patterns brings low pressure and high rainfall in the Western Pacific Brings high pressure and less rainfall in the Eastern Pacific Called ENSO Menu Previous Next 11 - 30

El Niño Southern Oscillation High pressure builds in the Western Pacific and low pressure

El Niño Southern Oscillation High pressure builds in the Western Pacific and low pressure in the Eastern Pacific Trade winds weaken or reverse and blow eastward – the southern oscillation This causes warm water of the west to migrate east to the coast of South America. The loss of upwelling deprives the water of nutrients - A normally productive region declines local fisheries collapse and marine ecosystems dwindle Over the eastern Pacific, humid air rises causing precipitation in normally arid regions. Flooding, tornados, drought etc can occur Menu Previous Next

El Niño Southern Oscillation Effects of ENSO. Menu Previous Next

El Niño Southern Oscillation Effects of ENSO. Menu Previous Next

El Nino and volcanoes strong correlation between seismic activity on the East Pacific Rise

El Nino and volcanoes strong correlation between seismic activity on the East Pacific Rise (indicates an eruption) and El Nino cycles over the past ~25 years Noticed by Dr. Dan Walker at the University of Hawaii large numbers of underwater volcanoes contribute toward the heating of the oceans 56 underwater volcanoes having confirmed eruptions in 2001 -2002 Menu Previous Next 11 - 33

Deep Circulation and Water Masses begins when water density increases due to cooling and

Deep Circulation and Water Masses begins when water density increases due to cooling and increased salinity the denser water sinks cold dense water stays on the bottom until mixing brings it back to the surface Tides and internal waves keep deep water mixed ocean stratifies into density layers Since water mass characteristics form at the surface, how do deeper layers get to the bottom? Menu Previous Next

Deep circulation and Water Masses Based on density stratification five generally recognized primary water

Deep circulation and Water Masses Based on density stratification five generally recognized primary water masses: To about 200 meters (600 feet) - surface water To the main thermocline (depth varies with latitude) - central water To about 1, 500 meters (5, 000 feet) - intermediate water Below intermediate water, but not in contact with the bottom, to about 4, 000 meters (13, 000 feet) - deep water In contact with the seafloor - bottom water Menu Previous Next

Deep Circulation and Water Masses Layers in the Sea Menu Previous Next

Deep Circulation and Water Masses Layers in the Sea Menu Previous Next

Deep circulation and Water Masses The Flow of Atlantic Deep Water Menu Previous Next

Deep circulation and Water Masses The Flow of Atlantic Deep Water Menu Previous Next

How Deep Water Masses Form intermediate, deep, and bottom water masses form primarily at

How Deep Water Masses Form intermediate, deep, and bottom water masses form primarily at high latitudes -around 70° North and South Antarctic Bottom Water and North Atlantic Deep Water, make up most of the world’s deep water Pacific Deep Water and Mediterranean Deep Water are also important The densest ocean water forms in the Antarctic during the winter Antarctic Bottom Water has a salinity of about 34. 65‰ and temperature of -0. 5˚C (31˚F) At the surface, its specific density is 1. 0279 grams per cubic centimeter, or almost 3% higher than pure fresh water Menu Previous Next

How Deep Water Masses Form This high density is due to low temperature and

How Deep Water Masses Form This high density is due to low temperature and high salinity As seawater freezes, it leaves salt behind The water that remains becomes saltier, explaining why Antarctic Bottom Water has such high salinity Menu Previous Next

How Deep Water Masses Form According to estimates, about 8 million cubic meters of

How Deep Water Masses Form According to estimates, about 8 million cubic meters of Antarctic Bottom Water form every second. very dense water descends to the bottom, spreads along the Antarctic deep-sea continental shelf and creeps northward Antarctic Bottom Water reaches as far as 40˚ north latitude, taking somewhat less than 1, 000 years to get there Antarctic Bottom Water is a primary source for both the deep and bottom water layers Menu Previous Next

How Deep Water Masses Form In the North Atlantic, high-salinity surface water cools and

How Deep Water Masses Form In the North Atlantic, high-salinity surface water cools and sinks. Pacific water that forms in the Northern Hemisphere is not as dense as deep bottom water, so it forms Pacific Intermediate Water. Intermediate water also develops in the North Atlantic, South Atlantic and South Pacific at latitudes that are not quite as cold as the Arctic or Antarctic. Mediterranean Deep Water forms due to evaporation rather than cooling. Menu Previous Next

How Deep Water Masses Form Water Masses This illustration shows a cross-section of the

How Deep Water Masses Form Water Masses This illustration shows a cross-section of the entire Atlantic Ocean looking eastward. Note how the different water masses float or sink, depending on their relative density. Circulation patterns are also indicated. Menu Previous Next

Deep Water Flow Patterns enormous water quantities sinking at the poles and in the

Deep Water Flow Patterns enormous water quantities sinking at the poles and in the Mediterranean are the source of the deep water masses and circulation. bottom water upwells to compensate rising warm water enters wind-driven currents and is carried to the poles cools, becomes more dense, and sinks again at the poles Menu Previous Next

The Ocean Conveyor Belt Interconnected flow of currents that redistribute heat Also called the

The Ocean Conveyor Belt Interconnected flow of currents that redistribute heat Also called the Earth’s air conditioner deep water and surface currents influence the Earth’s climate Menu Previous Next

Menu Previous Next 11 - 45

Menu Previous Next 11 - 45

The Ocean Conveyor Belt Deep water forms at high latitudes Water from the North

The Ocean Conveyor Belt Deep water forms at high latitudes Water from the North Atlantic Deep Water flows south along the Atlantic bottom, merging with Antarctic Bottom Water From there it flows eastward, with some flowing into the Indian Ocean, but most flowing to the South Pacific As the water mixes, it rises, warms, and eventually reaches the surface It is pushed by the trade winds around the ocean It carries heat from the equatorial regions north and south toward the poles It cools and descends, starting the cycle again Menu Previous Next

Gulf Stream from Franklin’s day Benjamin Franklin Was the first to map the gulf

Gulf Stream from Franklin’s day Benjamin Franklin Was the first to map the gulf stream Menu Previous Next 11 - 47

Gulf Stream presented ancient mariners with many challenges is almost 1 mile (1. 6)

Gulf Stream presented ancient mariners with many challenges is almost 1 mile (1. 6) kilometers deep and can move up to 26 billion gallons of water a second more than the flow of the Amazon River caused so many shipwrecks around Cape Hatteras, which juts out sharply from the east coast of North Carolina, that the area is called the graveyard of the Atlantic Menu Previous Next 11 - 48

Gulf Stream Carries a volume of water 100 x greater than Mississippi River 25

Gulf Stream Carries a volume of water 100 x greater than Mississippi River 25 x more water than all rivers in the world Has eddies at Western boundary Menu Previous Next 11 - 49

Mediterranean overflow current well-known density-driven current Where Mediterranean Sea empties into the Atlantic Ocean

Mediterranean overflow current well-known density-driven current Where Mediterranean Sea empties into the Atlantic Ocean During World War II, submarines used this current to enter and leave the Mediterranean without turning on their engines With a temperature of 13. 4 °C (56. 1 °F) and a salinity of 38. 4 ppt dense water forming in the Mediterranean Sea is both warmer and saltier than the North Atlantic Central Water (NACW) Menu Previous Next 11 - 50

Mediterranean overflow current NACW sits above the Mediterranean outflow of dense water, NACW has

Mediterranean overflow current NACW sits above the Mediterranean outflow of dense water, NACW has a temperature of 11. 4 to 12. 5 °C (52. 5 to 54. 5 °F) and a salinity that ranges from 35. 6 to 35. 7 ppt. Dense Mediterranean water moves westward into the North Atlantic through the bottom 100 metres (300 feet) of the Strait of Gibraltar, while North Atlantic water flows eastward through the upper part of the strait into the Mediterranean Sea. Given the narrow strait, the dense water accelerates to speeds of approximately 1 meter per second at the sill in the western part of the strait. After entering the Atlantic Ocean, the dense Mediterranean overflow current descends along the continental slope. Menu Previous Next 11 - 51

The Ocean Conveyor Belt in theory it would take 1, 000 to 2, 000

The Ocean Conveyor Belt in theory it would take 1, 000 to 2, 000 years for a single water molecule to complete a cycle on the ocean conveyor belt important because it has a great effect on the world’s climate. Menu Previous Next

The Ocean Conveyor Belt Hypothesize some of the coldest intervals within ice ages have

The Ocean Conveyor Belt Hypothesize some of the coldest intervals within ice ages have resulted from disruption of the ocean conveyor belt Hypothesize dilution of the North Atlantic Ocean with excess fresh water decreases the sinking of North Atlantic Deep Water If this thinking is correct, global warming may lead to an ice age Menu Previous Next

The Ocean Conveyor Belt Global warming increases the melting of glaciers and ice caps.

The Ocean Conveyor Belt Global warming increases the melting of glaciers and ice caps. This dilutes the seawater, preventing the high-density, salty water from forming Without this high-density water, there’s no downwelling to feed North Atlantic deep water currents This would disrupt the ocean conveyor belt by shutting down the transport of relatively warm water to the far North Atlantic, causing large parts of the Northern Hemisphere, especially Europe, to become much colder This probably occurred during the last ice age, but the possibility of happening now is speculative Menu Previous Next

Studying Ocean Currents Menu Previous Next

Studying Ocean Currents Menu Previous Next

Gulf stream/thermohaline circulation The Gulf Stream is a powerful surface current, driven by Trade

Gulf stream/thermohaline circulation The Gulf Stream is a powerful surface current, driven by Trade Winds. originates in the Gulf of Mexico carries the tropical waters from the Florida Strait to the great banks of the United States heads eastward, carrying its warm waters to the borders of the North Atlantic, where it splits As soon as the tropical waters hit the Arctic Ocean, they cool abruptly and plunge towards the abyssal zone forms a loop, known as "thermohaline circulation. " Acts like an immense conveyor belt that slows down in the ocean depths it goes southward to rejoin the beginning of the Gulf Stream
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The Gulf Stream & the Next Ice Age Climate Change is hot topic on

The Gulf Stream & the Next Ice Age Climate Change is hot topic on the political and social agenda internationally Our climate is changing industrial production, habitat, transportation and everyday human activities are acknowledged as causes of global warming So says Nicholas Koutsikas, director of The gulf stream and the next Ice age



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 http: //www. youtube. com/watch? v=Sy. AEucg 6 teg 51 minutes – The gulf

http: //www. youtube. com/watch? v=Sy. AEucg 6 teg 51 minutes – The gulf stream and the next ice age http: //www. iceagenow. com/Ocean_Warming. htm Link to many volcanoes warming the ocean http: //www. sciencedaily. com/releases/2008/01/08012 0160720. htm volcano under Antarctic ice http: //www. youtube. com/watch? v=o. BCtua. WKjl. U Arctic Sea Ice Has Grown To A Record Breaking Amount by Robert Felix 29 min Menu Previous Next 11 - 58